Conventionally, Patent Document 1 discloses a vehicle air conditioning device which performs heating of a vehicle compartment by heating blown air sent to the vehicle compartment by using, as a heat source, cooling water for an internal combustion engine that is an in-vehicle device emitting heat during operation (i.e. an engine outputting a driving force for vehicle travelling).
More specifically, the vehicular air conditioning device of Patent Document 1 includes a heater core which is a heating heat exchanger for heating the blown air by exchanging heat between the cooling water and the blown air. Furthermore, Patent Document 1 also describes that the blowing capacity of a blower that blows the blown air is increased as the temperature of the cooling water rises.